JPH07161068A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical information recording medium capable of high density recording and adaptable to an optical pickup using laser light of 630-700nm by incorporating a compd. represented by a specific general formula into an org. thin film. CONSTITUTION:An org. dye layer 2 as an org. thin film, an undercoat layer 3 and a protective layer 4 are laminated on a substrate 1 to obtain an optical information recording medium. When a compd. represented by the formula is incorporated into the layer 2, the optical information recording medium is obtd. as the objective optical information recording medium capable of high density recording and adaptable to an optical pickup using laser light of 630-700nm or the objective optical information recording medium for additional recording type CD or additional recording type CD-R having a long shelf life and less liable to deterioration due to reproduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium (hereinafter also abbreviated as a recording medium) used for a computer memory, a memory for image and audio files, an optical card and the like.

[0002]

2. Description of the Related Art A recording medium having an organic dye thin film as a recording layer is known in which a phthalocyanine compound is used for the organic dye thin film (Japanese Patent Laid-Open No. 183296/1983). 58-37851
No. Phthalocyanine compounds have the advantage of being extremely highly stable to heat and light, but have poor solubility in organic solvents, etc., and conventionally they can only be formed into thin films by the vapor deposition method, resulting in difficulty in productivity and easy association. , High refractive index,
There is a problem that a high reflectance cannot be obtained.

On the other hand, in recent years, semiconductor lasers having an oscillation wavelength (up to 680 nm) shorter than the wavelength range used in conventional optical disks have been put into practical use in order to achieve higher recording density. However, there is no conventional organic dye thin film having a light absorption ability and a light reflection ability in a wavelength range of 700 nm or less, and there is a limitation in high density recording property in terms of material.

Further, in a write-once compact disc type (CD-R) recording medium in which an organic dye thin film, a metal reflection layer and a protective layer are sequentially laminated on a substrate, a high reflectance is required to satisfy the CD standard. Therefore, it was necessary to develop an organic dye material having a high refractive index in the reproduction wavelength range (700 to 830 nm) and high stability.

Therefore, a first object of the present invention is to record a phthalocyanine compound having a high solubility in an organic solvent and a high productivity and a solvent coatable phthalocyanine compound as a recording material, while utilizing the characteristics of the phthalocyanine compound. It is to provide a medium. A second object of the present invention is 630 which enables high density recording.
To provide a recording medium applicable to an optical pickup using a semiconductor laser of ˜700 nm. A third object of the present invention is to provide a recording medium which has a high refractive index in the wavelength range of 770 to 830 nm and which can achieve a CD-R medium having a high reflectance and excellent storage stability and reproduction stability. Is to provide.

[0006]

[Means for Solving the Problems] A phthalocyanine compound is a macrocyclic planar compound and has a very high association property. Therefore, when it is made into a thin film, the absorption spectrum becomes broad and the reflectance (refractive index) also becomes low. is doing. Therefore, the present invention introduces a long-chain alkyl group at the α-position of the phthalocyanine ring and arranges the alkyl group at a right angle to the ring to prevent association, high absorptivity and high reflectance (refractive index). Is realized and the solubility in organic solvents is also improved.

That is, according to the present invention, an organic thin film layer is provided on a substrate directly or through an undercoat layer, and if necessary,
In an optical information recording medium having a protective layer provided thereon,
There is provided an optical information recording medium, characterized in that the organic thin film layer contains a compound represented by the following general formula (I).

[Chemical 1]

Further, according to the present invention, a write-once compact disc type recording medium is provided which is provided with a metal reflection layer between the organic thin film layer and the protective layer and records a CD format signal. The optical information recording medium is provided.

The present invention will be described in detail below. First, the configuration of the recording medium will be described. FIG. 1 is a diagram showing an example of a layer structure applicable to the recording medium of the present invention, in which an organic thin film layer 2 is provided on a substrate 1 via an undercoat layer 3 if necessary,
Further, a protective layer 4 is provided if necessary.

FIG. 2 is a diagram showing another example of the layer structure of another type applicable to the recording medium of the present invention, in which the metal reflection layer 5 is provided on the organic thin film layer 2 having the structure shown in FIG.

The recording medium of the present invention may have an air sandwich structure in which the organic thin film layer (recording layer) having the structure shown in FIGS. 1 and 2 is placed inside and sealed with another substrate through a space, Alternatively, a laminated structure in which the protective layer is adhered may be used.

Next, the required characteristics of the constituent layers and the constituent materials thereof will be described. 1) Substrate As a necessary characteristic of the substrate, when recording / reproducing is performed from the substrate side, it must be transparent to the laser light used, but when recording / reproducing from the recording layer side, it is not necessary to be transparent. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramic or metal can be used. A guide groove or guide pit for tracking and a preformat such as an address signal may be formed on the surface of the substrate.

2) Recording Layer The recording layer is capable of recording some information by causing some kind of optical change by irradiation of laser light, and the phthalocyanine compound of the general formula (I) is contained in this recording layer. Must be included. In forming the recording layer, the compounds of the present invention may be used alone or in combination of two or more. Furthermore, the compound of the present invention is another dye, for example, polymethine dye, naphthalocyanine type, squarylium type, croconium type, pyrylium type, naphthoquinone type, anthraquinone (indanthrene) type, xanthene type, triphenylmethane type, azulene type, You may use it combining with a tetrahydrocholine type | system | group, a phenanthrene type | system | group, a triphenothiazine type | system | group dye, or a metal complex compound. In this case, the above dyes may be used alone or in combination of two or more.

Further, the compound of the present invention is a metal or a metal compound such as In, Al, Te, Bi, Al, Be, Te.
O ₂ , SnO, As, Cd and the like can also be used in the form of dispersion mixing or lamination. Further, various materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, or silane coupling agents are dispersed and mixed in the compound of the present invention and used. Alternatively, it may be used together with a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer or the like for the purpose of improving properties.

The recording layer is formed by vapor deposition, sputtering, C
It can be carried out by a conventional means such as VD or solvent coating. When the coating method is used, the above compounds and the like are dissolved in an organic solvent and a conventional coating method such as spraying, roller coating, dipping or spinner coating is used.
As the organic solvent, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexane, amides such as N, N-dimethylacetamide and N, N-dimethylformamide, sulfoxides such as dimethyl sulfoxide and tetrahydrofuran. , Ethers such as dioxane, diethyl ether and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate,
Aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane, and aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene can be used. The thickness of the recording layer is 100 Å to 10 μm, preferably 200 Å to 10 μm in the case of the medium structure shown in FIG.
00Å is suitable, and in the case of the medium structure shown in FIG.
300 Å to 5 μm, preferably 500 Å to 2000 Å is suitable.

3) Undercoat layer The undercoat layer has (a) improved adhesion, (b) barrier against water or gas, (c) improved storage stability of the recording layer, and (d) improved reflectance. , (E) protection of the substrate from solvent, (f) formation of guide grooves, guide pits, preformats, etc. For the purpose of (a), it is possible to use various polymers such as ionomer resins, polyamides, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and various silane coupling agents. For the purposes of (b) and (c), an inorganic compound such as SiO 2 may be used in addition to the above polymer material.
₂ , MgF ₂ , SiO, TiO ₂ , ZnO, TiN, Si
N, Zn, Cu, Ni, Cr, Ge, Se, Au,
A metal such as Ag or Al or a semi-metal can be used. For the purpose of (b), a metal such as A
l, Ag, or the like, or an organic thin film having a metallic luster, such as a methine dye or a xanthene dye, can be used.
For the purposes of (e) and (f), an ultraviolet curable resin,
A thermosetting resin, a thermoplastic resin or the like can be used.
The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.1.
05-10 μm is suitable.

4) Metal reflective layer For the metal reflective layer, a metal, a semimetal, or the like, which alone has a high reflectance and is resistant to corrosion, can be used. As a specific material,
Examples thereof include Au, Ag, Cu, Al, Cr, Ni and Al, and Au and Al are preferable. These metals and semimetals may be used alone or as an alloy of two or more kinds. Examples of the film forming method include vapor deposition and sputtering, and the film thickness is 50 to 3000 Å, preferably 1
It is from 00 to 1000Å.

5) Protective Layer, Substrate Surface Hard Coat Layer The protective layer or substrate surface hard coat layer (a) protects the recording layer from scratches, dust, dirt, etc. (b) Improves storage stability of the recording layer , (C) used for the purpose of improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used. In addition, as an inorganic material, S
It is also possible to use iO, SiO _2, etc., and as an organic material, acrylic resin, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, styrene-butadiene. Resins, chloroprene rubber, waxes, alkyd resins, drying oils, heat-softening and heat-melting resins such as rosin can also be used. Among the above materials, the most preferable one for the protective layer or the substrate surface hard coat layer is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm.
m, preferably 0.05 to 10 μm. In the present invention, the undercoat layer and the protective layer may contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer and the like at the same time as the recording layer.

[0020]

The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Example 1 A substrate having a guide groove having a depth of 850Å, a half value width of 0.3 μm, and a track pitch of 1.3 μm was formed on a polymethylmethacrylate plate having a thickness of 1.15 mm with a photopolymer of 50 μm. In the general formula (I), R _{1 to} R ₈ are
A chloroform solution of a compound of nC ₅ H ₁₁ was spinner-coated and a recording layer having a thickness of 700Å was provided to obtain a write-once recording medium.

Examples 2 to 4 In Example 1, R _{1 to} R ₈ in the general formula (I) are used.
Is -nC ₅ H ₁₁ , instead of R ₁ ~
Recording media of Examples 2 to 4 were obtained in the same manner except that compounds in which R ₈ was -nC ₆ H ₁₃ , -nC ₈ H ₁₇ , and -nC ₁₂ H ₂₅ were used.

Comparative Example 1 In Example 1, R _{1 to} R ₈ in the general formula (I) are used.
Instead of but compounds which are _{-nC 5 H 11, R 1 ~R} 8 is H
A recording medium of Comparative Example was obtained in the same manner except that the compound of was used.

Comparative Example 2 In Example 1, R _{1 to} R ₈ in the general formula (I) are used.
Is -nC ₅ H ₁₁ , instead of R ₁ , R ₃ ,
R _5, R ₇ to obtain a recording medium of Comparative Example in the same manner except for using _{-nC 6 H 13, R 2,} R 4, R 6, R 8 is H compound.

The above Examples 1 to 4 and Comparative Example 1,
Using the recording medium of No. 2, recording was performed through the substrate under the following recording conditions, then the recording position was reproduced with continuous laser light, and the C / N was measured under the following conditions. The reflectance was also measured. The results are shown in Table 2. Recording conditions: linear velocity 2.1 m / sec recording frequency 1.6 MHz laser oscillation wavelength 680 nm pickup lens N.P. A. 0.5 Playback condition: Scanning filter 30KHz Playback power 0.3mW

[0026]

[Table 2]

Example 5 R _{1 to} R in the above general formula (I) on an injection-molded polycarbonate substrate having a depth of 1000 Å, a half width of 0.4 μm and a guide groove having a track pitch of 1.6 μm and a thickness of 1.2 mm. A 1,1,2-trifluoroethanol solution of the compound in which ₈ is -nC ₆ H ₁₃ is spinner coated to a thickness of about 1
A recording layer of 500 Å is provided, 1000 Å of Au is sputtered on the recording layer to form a reflective layer, and a protective layer having a thickness of about 2 μm is formed on the reflective layer with an acrylic photopolymer.
The recording medium was a CD-R type.

Examples 6 to 7 In Example 5, R _{1 to} R ₈ in the general formula (I) are used.
Is -nC ₆ H ₁₃ , instead of R ₁ ~
Recording media of Examples 6 to 7 were obtained in the same manner except that compounds having R ₈ of -nC ₈ H ₁₇ and -nC ₁₂ H ₂₅ were used.

Comparative Example 3 A recording medium of Comparative Example was obtained in the same manner as in Example 5, except that the compound of the following general formula (II) was used as the recording material.

[Chemical 2]

Comparative Example 4 In Example 5, R _{1 to} R ₈ in the general formula (I) are used.
There, instead of the compound which is _{-nC 6 H 13, R 1,} R 3,
R _5, R ₇ to obtain a recording medium of Comparative Example in the same manner except for using the compound _{-nC 8 H 17, R 2,} R 4, R 6, R 8 is H.

Using the recording media of Examples 5 to 7 and Comparative Examples 3 and 4, EFM signals were recorded under the recording conditions of a wavelength of 790 nm and a linear velocity of 1.3 m / sec, and reflection was performed before recording and after irradiation with tungsten light. The rate and the jitter of 3T bits were measured. The results are shown in Table 3.

[Table 3]

[0032]

EFFECTS OF THE INVENTION 1) High light absorption and light reflectivity at wavelengths of 630 to 700 nm enable high density recording of 630 to 700 n.
With a recording medium that can be applied to a pickup using a m laser, it is possible to achieve a recording density of 1.6 to 1.7 times higher than that of the current recording medium compatible with 780 to 810 nm. 2) Since it has a high refractive index in the wavelength range of 770 to 830 nm and a high stability, it is possible to provide a recording medium for CD-R having a high reflectance and excellent storage stability and reproduction stability. .

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a layer structure applicable to a recording medium of the present invention.

FIG. 2 is a diagram showing an example of another type of layer structure applicable to the recording medium of the present invention.

[Explanation of symbols]

 1 Substrate 2 Organic Dye Layer 3 Undercoat Layer 4 Protective Layer 5 Metal Reflective Layer

Claims (2)

[Claims] 1. An optical information recording medium in which an organic thin film layer is provided on a substrate directly or via an undercoat layer, and a protective layer is optionally provided thereon, in the organic thin film layer, the following general An optical information recording medium comprising a compound represented by formula (I). [Chemical 1] 2. A write-once compact disc type recording medium comprising a metal reflective layer provided between the organic thin film layer and the protective layer and recording a CD format signal. Optical information recording medium.